{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "69e73122-d809-4d2f-b52f-448050ac5820",
   "metadata": {},
   "source": [
    "# プロと読み解く Ruby 3.0 NEWS"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "dfc8ecef-5544-41aa-895b-e8228a1a6923",
   "metadata": {},
   "source": [
    "### 式展開を含む文字列リテラルは、frozen-string-literal: true で freeze しなくなった"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "db19de7a-fbdc-42c9-a1c4-47e9a5956566",
   "metadata": {},
   "source": [
    "``` ruby\n",
    "# frozen-string-literal: true\n",
    "\n",
    "p \"foo\".frozen? #=> true\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "7390c2ec-652e-434c-9722-28140460eedd",
   "metadata": {},
   "source": [
    "``` ruby\n",
    "# frozen-string-literal: true\n",
    "\n",
    "p \"foo#{42}bar\".frozen? #=> true\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "f16c40c4-03c7-42dc-b126-746a30485dcf",
   "metadata": {},
   "source": [
    "## 組み込みクラスのアップデート"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "d80740d9-bc4f-4df0-8126-7aea7bdb2f7b",
   "metadata": {},
   "source": [
    "### Array のサブクラスのメソッドが、サブクラスではなく、Array クラスのオブジェクトを返すようになった"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "9e2706d2-7f69-4422-b255-f59b973c064b",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[2, 3]\n",
      "Array\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "Array"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "class MyArray < Array\n",
    "end\n",
    "\n",
    "ary = MyArray.new([1, 2, 3]).drop(1)\n",
    "\n",
    "p ary       #=> [2, 3]\n",
    "p ary.class #=> MyArray  # 2.7\n",
    "ary.class #=> Array    # 3.0"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Ruby 3.0.0",
   "language": "ruby",
   "name": "ruby-3.0.0"
  },
  "language_info": {
   "file_extension": ".rb",
   "mimetype": "application/x-ruby",
   "name": "ruby",
   "version": "3.0.0"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 5
}